Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

PDF

Theses/Dissertations

2013

University of Arkansas, Fayetteville

Discipline
Keyword
Publication

Articles 91 - 108 of 108

Full-Text Articles in Life Sciences

Modeling Greenhouse Gas Emissions And Net Return Implications For Cow-Calf Producers In The Ozark Highlands, Stephen Aaron Smith May 2013

Modeling Greenhouse Gas Emissions And Net Return Implications For Cow-Calf Producers In The Ozark Highlands, Stephen Aaron Smith

Theses and Dissertations

Cow-calf producers in the Ozark Highlands region are under continuous pressure to improve economic efficiency. Additionally, estimating greenhouse gas (GHG) emissions from cow-calf and forage production processes may become increasingly important as policy makers seek to mitigate or reduce agriculture's role in climate change. As such, this analysis had three objectives. Objective 1: Provide a model that could be used by cow-calf producers, extension agents, and researchers to evaluate GHG and net return (NR) repercussions when modifying site characteristics, production methods, and inputs. Objective 2: Develop a user guide such that the methodology for estimating cow-calf GHG emissions and ...


Biodiesel Transesterification Byproducts As Soil Amendments, Solomon Parker May 2013

Biodiesel Transesterification Byproducts As Soil Amendments, Solomon Parker

Theses and Dissertations

For every ten kilograms of biodiesel that is produced from the transesterification of vegetable oil, approximately 1 kg of glycerol is produced as a byproduct. Also known as glycerin, it is a chemical used in many products including cosmetics, foods, and desiccants. However, the crude glycerol created during biodiesel production is tainted with potassium hydroxide and methanol making it unsuitable for commercial use without costly refinement. With increase in production of biodiesel driven by rising fuel prices, the market has become glutted with glycerol and it is on the threshold of becoming a waste product. Common methods for disposing glycerol ...


An Analysis Of Firearms Training Performance Among Active Law Enforcement Officers, John Thomasson May 2013

An Analysis Of Firearms Training Performance Among Active Law Enforcement Officers, John Thomasson

Theses and Dissertations

Firearms proficiency is an implicit expectation, held by the public of police officers, due to presumption that the required firearm training is an adequate preparation for a deadly force encounter. However, anecdotal evidence and available data on police shootings suggest that conventional, unrealistic training methods are wholly inadequate. To present stress into firearms training, some departments have opted for exercises such as physical exertion and shoot-house training as a substitute for realistic simulation of force-on-force confrontations.

To determine whether such exercises are comparable, an observation of performance and heart rate levels was conducted on a group of eight police officers ...


Expression, Production, And Purification Of Novel Therapeutic Proteins, Mckinzie Shea Fruchtl May 2013

Expression, Production, And Purification Of Novel Therapeutic Proteins, Mckinzie Shea Fruchtl

Theses and Dissertations

Interest in the production of recombinant proteins consisting of collagen binding domain (CBD) fused to a bioactive material has increased due to the targeting/attachment capabilities of CBD. For example, CBD fusions can be applied to the reversing of bone density loss and the repair of the eardrum, specifically, by choosing an appropriate fusion partner (parathyroid hormone or epidermal growth factor). The production of CBD fusions was examined using batch and fed-batch culturing of Escherichia coli to express the fusion proteins, and affinity chromatography to isolate the final product.

Different medium formulations, feeding strategies, and induction methods were tested in ...


Oxidation Of Thrombomodulin Methionine 388 In Cigarette Smokers, Samrat B. Thapa May 2013

Oxidation Of Thrombomodulin Methionine 388 In Cigarette Smokers, Samrat B. Thapa

Theses and Dissertations

This work tested the hypothesis that oxidation of methionine 388 in thrombomodulin is higher in cigarette smokers, and thus a likely contributor towards the hypercoagulable state in smokers. Thrombomodulin, a protein cofactor found on endothelial cell surfaces, regulates the activity of thrombin. Thrombin bound to thrombomodulin no longer converts fibrinogen to fibrin, but instead activates Protein C which, in turn, stops the coagulation cascade by inactivation of clotting factors. The oxidation of methionine 388 of thrombomodulin has been shown in vitro to dramatically decrease the anticoagulant cofactor activity of thrombomodulin. The blood of cigarette smokers is more prone to clot ...


Local Food And Agriculture Awareness: The Literacy Of Local Produce And Agriculture In Northwest Arkansas, Kyle Colton Flynn May 2013

Local Food And Agriculture Awareness: The Literacy Of Local Produce And Agriculture In Northwest Arkansas, Kyle Colton Flynn

Theses and Dissertations

The Center for Disease Control and Prevention (CDC) suggests that adolescents and children, both male and female, are failing to meet the daily fruit and vegetable consumption requirements (Kim et al., 2011; Upton et al., 2012; Harris et al., 2012). Other studies have shown that with increased exposure and availability of produce, students (K-5) tend to consume more fruits and vegetables (Cullen et al., 2009; Evans et al., 2012). The purpose of this study is to identify whether Northwest Arkansas eleventh grade high school students possess experience and knowledge of local produce and agriculture. Out of 1054 students enrolled at ...


Influence Of Horn Flies And Breed Type On Milk Production, Calf Production Traits, Pasture Behavior, And Temperament Measurements In Beef Cattle, Angela Rene Mays May 2013

Influence Of Horn Flies And Breed Type On Milk Production, Calf Production Traits, Pasture Behavior, And Temperament Measurements In Beef Cattle, Angela Rene Mays

Theses and Dissertations

An experiment conducted in El Reno, Oklahoma during the fly season (May - September/October) evaluated the effects of horn flies on milk production, calf performance, and pasture behavior and temperament measurements of beef cow calf pairs. Cows (n = 53) sired by Bonsmara (BONS; n = 7), Brangus (BRAN; n = 13), Charolais (CHAR; n = 8), Gelbvieh (GELV; n = 5), Hereford (HERF; n = 12), and Romosinuano (ROMO; n = 8) from Brangus dams and their Angus sired calves (n = 51) were used in the study. Horn fly counts (HFC) and milk yield and quality estimates were collected every 28 d from May to October ...


Dynamics And Model Of The Pore-Forming Protein Lysenin, Eric Krueger May 2013

Dynamics And Model Of The Pore-Forming Protein Lysenin, Eric Krueger

Theses and Dissertations

Membrane transporters are a class of membrane proteins that function to provide a pathway across a cell membrane for the movement of ions and biomolecules. Investigations into the regulatory mechanism of these systems are hindered by their extensive preparation requirements compounded by their fragility and instability. However, lysenin, a pore-forming protein extracted from the earthworm Eisenia foetida, provided a unique opportunity to study a protein which is stable in both a soluble and membrane phase. Lysenin channels possess several important properties characteristic of ion channels without the inherent difficulties that plague investigations with biologically vital membrane transporters like voltage-gated ion ...


Effects Of Ergot Alkaloids And Bovine Bodily Fluids On Cytochrome P450 Activity, Nicholas Scott Ezell May 2013

Effects Of Ergot Alkaloids And Bovine Bodily Fluids On Cytochrome P450 Activity, Nicholas Scott Ezell

Theses and Dissertations

This thesis evaluates the PromegaTM P450-Glo assay (PromegaTM V9800) as a tool for quantifying ergot alkaloid concentration. Current techniques used for detection of ergot alkaloids are slow and expensive, do not detect all ergot alkaloids, or are not effective on bovine bodily fluids. The first study was conducted to determine effects of commercial ergot alkaloids (n = 6; 0 - 400 μM) on the PromegaTM P450-Glo assay. Cytochrome P450 (CYP450) activity in assay had a differential response to each ergot alkaloid and concentration. As concentrations of ergotamine, dihydroergotamine, ergocornine, and ergocryptine increased CYP450 activity was inhibited (P < 0.05). Increases in ergonovine and pergolide concentration did not affect (P > 0.1 ...


Using The Ceres-Maize Model To Create A Geographically Explicit Grid Based Estimate Of Corn Yield Under Climate Change Scenarios, Ryan Zachary Johnston May 2013

Using The Ceres-Maize Model To Create A Geographically Explicit Grid Based Estimate Of Corn Yield Under Climate Change Scenarios, Ryan Zachary Johnston

Theses and Dissertations

The CERES-Maize model was evaluated in its capacity to predict both regional maize yield and water use within the United States Department of Agriculture (USDA) Economic Research Service (ERS) Region 1 between the years 1997-2007. A grid based, geospatially explicit method was developed to express the various rainfed and irrigated maize cultivars grown across the region. Overall, the calibrated model compared well for both physiological and yield parameters, producing significant linear relationships (p

The calibrated and validated CERES-Maize model was used to predict potential evapotranspiration and yield under three IPCC weather scenarios for the year 2050 to evaluate crop production ...


Litter Conditioning Is Differentially Affected By Leaf Species, Phosphorus Enrichment, And Light Availability, Erin E. Scott May 2013

Litter Conditioning Is Differentially Affected By Leaf Species, Phosphorus Enrichment, And Light Availability, Erin E. Scott

Theses and Dissertations

Anthropogenic enrichment of nitrogen and phosphorus is one of the most pervasive and detrimental threats to aquatic ecosystems worldwide. In streams that rely on allochthonous basal food resources, such as leaves, nutrient pollution can result in altered food quality and decreased carbon (C) standing stocks. However, the magnitude and mechanisms of this change in quality are poorly understood. Laboratory microcosm studies were conducted to 1) quantify the response of litter C:P to a gradient of phosphorus (P) enrichment (0, 0.05, and 0.5 mg SRP/L) across leaf species with variable levels of degradability (sugar maple and oak ...


Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri) In Arkansas: Resistance Mechanisms And Management Strategies, Griff Michael Griffith May 2013

Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri) In Arkansas: Resistance Mechanisms And Management Strategies, Griff Michael Griffith

Theses and Dissertations

Since 2000, there have been thirteen weed species confirmed resistant (R) to glyphosate in the United States, six of those resistant species are present in Arkansas. The goal of this research was to confirm and to determine the level of resistance in two R Palmer amaranth biotypes from Mississippi (MC-R) and Lincoln (LC-R) Counties, Arkansas, and one susceptible (S) biotype from Clarendon County, South Carolina, which had never been exposed to glyphosate. Shikimic acid concentration over time was significantly greater in the S biotype than both the MC-R and LC-R biotypes. The lethal dose required to kill 50% (LD50 ...


Effects Of Using Canola Meal As A Protein Source In Broiler Diets, Charles Danny Bradley Jr May 2013

Effects Of Using Canola Meal As A Protein Source In Broiler Diets, Charles Danny Bradley Jr

Theses and Dissertations

Six experiments were conducted to evaluate the response of broilers fed canola meal. Experiment 1 assessed performance and carcass yields when broilers were fed various combinations of canola and soybean meal in nutritionally balanced diets based on digestible amino acid values. The results suggested that canola meal can be used in isocaloric diets as a partial replacement for Soybean meal.

Experiment 2 assessed broiler performance and carcass yields when using various levels of canola meal in broiler diets with a constant level of supplemental poultry oil. The resulting data suggested when diets are formulated with a constant level of supplemental ...


Groundcover Management System And Nutrient Source Impact Physical Soil Quality Indicators In An Organically Managed Apple Orchard, Neal Mays May 2013

Groundcover Management System And Nutrient Source Impact Physical Soil Quality Indicators In An Organically Managed Apple Orchard, Neal Mays

Theses and Dissertations

In March 2006, four groundcover management systems (GMS) and two nutrient sources (NS) were implemented for their ability to alter the soil physical condition of a newly established, organically managed apple (Malus x domestica Borkh.) orchard. Annual applications of municipal green compost (GC), shredded office paper (SP), wood chips (WC), and mow-blow (MB) grass mulch were utilized as GMS, and NS supplied to trees were from composted poultry litter (PL), a commercial organic fertilizer (CF), or an untreated control (NF) in a 4x3 factorial study. An established, conventionally-managed orchard was located adjacent to the organic research orchard on the same ...


Relationship Of Lactate Dehydrogenase & Prolactin Genotypes To Immune Function, Growth, And Composition Of Replacement Heifers Grazing Tall Fescue, Christina Marie Turner May 2013

Relationship Of Lactate Dehydrogenase & Prolactin Genotypes To Immune Function, Growth, And Composition Of Replacement Heifers Grazing Tall Fescue, Christina Marie Turner

Theses and Dissertations

Objectives of this research were to determine effects of LDH enzymatic activity and circulating PRL on immune response, growth, composition, and reproduction, and to determine the effects of single nucleotide polymorphisms of LDH and PRL on immune function, growth and carcass traits, cyclicty, and fecundity of replacement heifers grazing endophyte infected tall fescue. Eighty-nine Angus based heifers had physical and ultrasound measurements along with blood samples collected at weaning, yearling, and prebreeding. Estrus detection was conducted for 10 d post each collection period, except prebreeding. Pregnancy status was verified after AI and again after bull removal. Heifers were maintained on ...


Interactions Between Ions And Lysenin Nanochannels And Their Potential Applications As Biosensors, Radwan Awwad Al Faouri May 2013

Interactions Between Ions And Lysenin Nanochannels And Their Potential Applications As Biosensors, Radwan Awwad Al Faouri

Theses and Dissertations

Lysenin is classified as a pore-forming toxin protein that is isolated from the earthworm Eisenia fetida and consists of 297 amino acids [1]. Lysenin inserts large conducting pores (3.0-4.7 nm in diameter) into artificial membranes (BLM) which include sphingomyelin. These pores (channels) are open and oriented upon insertion into the bilayer lipid membrane. Lysenin channels gate at positive voltages (voltage-induced gating), but not at negative voltages. Lysenin pores also exhibit activity modulation in response to changes in ionic strength and pH, indicating that electrostatic interaction is responsible for Lysenin conductance activities. In this line of inquiries, and by ...


Development Of A Predictive Modeling System For Validation Of The Cumulative Mirobial Inactivation Of The Salmonellae In Pepperoni Utilizing A Non-Pathogenic Surrogate Microorganism (Enterococcus Faecalis), Scott Donald Stillwell May 2013

Development Of A Predictive Modeling System For Validation Of The Cumulative Mirobial Inactivation Of The Salmonellae In Pepperoni Utilizing A Non-Pathogenic Surrogate Microorganism (Enterococcus Faecalis), Scott Donald Stillwell

Theses and Dissertations

Salmonellosis is the most frequently occurring bacterial foodborne illness in the United States and the human case rate has not improved for the past two decades. The federal agency responsible for oversight of meat and poultry processors has announced the intent to extend existing pathogen reduction performance standards for Salmonella spp. to cover all classes of products including fermented sausages that are currently produced under HACCP plans that are validated for control of Escherichia coli O157:H7. The proposed regulatory modifications will require processors to revalidate HACCP plan controls to achieve either a 6.5 or a 7.0 log10 ...


Efficacies Of Fenbendazole And Albendazole In The Treatment Of Commercial Turkeys Artificially Infected With Ascaridiadissimilis, Jessica Perkins May 2013

Efficacies Of Fenbendazole And Albendazole In The Treatment Of Commercial Turkeys Artificially Infected With Ascaridiadissimilis, Jessica Perkins

Animal Science Undergraduate Honors Theses

The goal of this research was to determine the extent of anthelmintic resistance that turkey roundworms, Ascaridiadissimilis, have developed to anti-parasitic chemicals used in commercial turkey operations. Roundworm infections in turkeys have resulted in monetary losses for the poultry industry for years, generally due to poor feed conversion. The infection itself is generally subclinical and many turkeys have a light to moderate worm burden. Since parasitisms are light, this leads to the infections being noticed only during processing.A. dissimilis infections consist of adult worms and developing larvae with the latter comprising most of the worm burden and causing the ...